1. Field of the Invention
This invention relates to methods of waterproofing porous concrete or masonry subterranean walls and foundations; and more particularly, pertains to methods for creating a waterproof barrier on the exterior or soil side of a subterranean, concrete or masonry foundation or wall.
2. Brief Description of the Prior Art
Concrete and masonry foundations such as found in basements of buildings or in underground vaults (such as contain utility power station gathering in distribution systems) are porous, and water seeps through steadily, unless halted by a waterproof barrier inside or outside the wall.
Water seepage into an underground basement or vault often results from settling of a foundation. The foundation footing rests on the soil and supports the entire weight of the superstructure. Some parts of the footing may be weaker than others, and the result is an uneven distribution of the weight, often stressing the wall such that it cracks, creating an entrance place for moisture.
Poor workmanship in the construction of a wall or foundation is a cause of water entry. Sometimes the grade of mortar used in the laying of a concrete block foundation is inadequate or the mortar does not make a solid bond between the blocks, and water from the ground outside penetrates. Alternatively, when the foundation is solid concrete, it can have been poured in layers with an imperfect bond made between the layers.
Seepage may be the result of heavy ground moisture. Areas in which there are clay subsoils, high water tables, or other poor drainage conditions can result in a tremendous force being exerted by water in the ground that will drive the water through pores of the wall. The conventional cure for water seepage in subterranean walls and/or foundations has been to coat the inside or basement surface of the wall with a waterproofing compound applied to unpainted masonry or concrete. Another cure has been to pour a latex solution into the ground directly above where a crack in the wall starts. The latex solution makes its way down, following microscopic channels created by the water that found its way into the basement, and finally flows into the crack itself. As it flows it sets up; fully setup it fills both channels and cracks until they are closed completely. When the ground to be treated is sealed off by a hard surfacer, such as a concrete walk or drive or other finish, a hole is drilled through the surfacer as close to the wall as possible and the latex solution is poured through the holes to find a crack in the wall, or a hole is drilled through the basement wall below ground level and a tube is inserted into the hole long enough to reach the soil outside, with the latex patcher solution being poured through the tube to the outside wall. The hole in the wall is then filled with a patcher.
Finally, a less convenient but longer lasting cure heretofore has been to completely evacuate the ground around the outside walls of the basement or vault so that the wall can be waterproofed all the way down to the footing. In this, a waterproofing mastic is applied to the wall, followed by several coats of asphalt paint, then asphalt paper, and then finally another coat of asphalt paint, after which the evacuated area is back filled and sloped away from the wall.
The foregoing methods are not wholly satisfactory in waterproofing subterranean walls. Waterproofing compound applied to interior walls eventually disintegrates as it looses adhesion under pressure of water seepage from the outside. Latex solutions applied to the outside utilizing gravity forces often do not set up well in a wet soil and are largely a hit or miss solution. Application of an asphalt coating to the outside requires excavation of the soil, and even after applied, is subject to dissolution by hydrocarbons as might spill from a tank truck adjacent the wall. Asphalts are also subject to shrinkage retraction upon drying, and with alternating wet and dry exposure can suffer cracks that undo the coating.